State-of-the-art wind tunnel advances hypersonic flight research
Alysa Guffey | Wednesday, November 20, 2019
Faculty and students at the Notre Dame Hypersonic Aerodynamics Lab unveiled the largest quiet Mach 6 hypersonic wind tunnel in the United States on Nov. 30, 2018. Nearly a year later, the lab continues to apply the technology to the future of flying.
Thomas Juliano, assistant professor of aerospace and mechanical engineering, established the lab and began the project in August 2014. Juliano said his motivation behind the project is the possibility of hypersonic flight in the future.
“The story of transportation for the last 2,000 years has been finding ways to go faster and faster,” Juliano said. “This is merely the latest step in that.”
Juliano previously worked with a smaller-scale quiet wind tunnel as a graduate student at Purdue University before coming to Notre Dame.
“We can do a lot with that, but we want to be able to test longer models in order to see more of what’s going on,” Juliano said. “The logical next step for facility development in order to unlock these other investigations in fluid mechanics was to build a larger-scale item.”
Challenges for hypersonic flight include extremely high temperatures that surround aircraft when going thousands of miles per hour, said first-year doctoral student Andrew Bustard.
“The high-heating rates, if not designed around, will destroy your vehicle,” Bustard said. “Obviously, we don’t want that. But the flow physics is so complex that we don’t actually understand fully what’s causing the heating or the best way to reduce it, so the whole point of this group is to study the flow around objects around potential or get a better understanding of the flow around high-speed objects.”
The Mach 6 quiet wind tunnel is unique as it better replicates the silent noise that occurs in the atmosphere, Bustard said.
“Most facilities we have on the ground have way more noise than in the atmosphere,” Bustard said. “If we truly want to model the heating in the atmosphere, we need to have flow in our wind tunnel that represents those atmospheric conditions. [The quiet tunnel] better matches the atmosphere, and that’s why it’s very useful for us.”
The Mach 6 tunnel project has provided opportunities for multiple engineering students to get involved in hypersonic research. Erik Hoberg, a third-year doctoral student, specializes in flow characterization and wind tunnel design. He has been involved in the project for a little over a year.
”I was not part of [Juliano’s] group when I came to Notre Dame,” Hoberg said. “Then I met him and saw what his group was doing and really wanted to be on that project.”
Fifth-year doctoral candidate Carson Running has helped with the quiet tunnel since his first year of graduate school. He worked heavily on the design and building of the tunnel in the early years of the project.
“One question that I researched was the best way to heat the large surface area [of the wind tunnel],” Running said. “We actually found a company down in Texas that sells these big long heating blankets that can just be wrapped around the steel portions of the wind tunnel and set to a certain temperature that we desire.”
Running spoke to the challenges of designing a state-of-the-art quiet tunnel that can advance the progress of hypersonic flight.
“A lot of the problems we’re trying to solve from small to big haven’t really been solved before, so overcoming that was … doing a lot of research but also a ton of collaboration and meetings with professor Juliano, using his expertise and kind of working together,” Running said. “One thing that I always like that [Juliano] says when he assigns projects or assignments to us is, ‘I wouldn’t be assigning them to you if I knew how to do them.’ He really does need our help and is willing to work with us and bounce ideas off of each other.”